#include <iostream>
#include <cstring>

int main()
{
    // char str[20] = "hello world"; //字符数组:将hello world字符串转给数组 发生了内存的拷贝
    // const char *s = "hello world";//将一个指针指向一个常量取得字符串
    std::string s = "hello world";
    s = s + " nihao";
 
    std::cin>>s;
    std::cout<<s.size()<<std::endl;
    std::cout<<s<<std::endl;
    return 0;
}